What is the value of a 1938 liberty head nickel in mint condition?

The last Liberty nickels were minted for circulation in 1912.

If you have a Buffalo nickel with that date and a small "D" underneath the Words 'FIVE CENTS' on the coin's reverse, it is worth about $4 in XF condition.

If you use a strong magnifying glass and can see a shadow of the letter "S" underneath the D, you have a rarer issue that is worth $20-$25 in XF.